2007: Purdue pays more than $600 million to settle government charges that it trained its sales representatives to mislead physicians about the risks of addiction and overdose from OxyContin.

2010: A tamper-resistant reformulation of OxyContin is released.

2013: A Purdue scientist attends a conference on drug dependency and presents a study of suspected risky prescribers. The study concludes that a small number of physicians may be responsible for a "substantial portion" of painkillers being diverted to the streets.